This invention relates to the conversion of chemical energy to electrical energy. In particular, the present invention relates to a new sandwich cathode design having two cathode active materials provided on opposite sides of a current collector. The respective cathode active materials are similar in terms of, for example, their rate capability, their energy density, or some other parameter. However, one material may have an advantage over the other in one characteristic, but be disadvantageous in another.
The cathode is built in a sandwich configuration having a first one of the cathode active materials sandwiched between two current collectors. Then, a second one of the cathode active materials is provided in contact with at least the other side of one of the current collectors, and preferably facing the anode. Such a construction enables the beneficial aspects of each of the active materials to be accentuated, while diminishing their unfavorable characteristics.
Accordingly, the object of the present invention is to improve the performance of lithium electrochemical cells by providing a new concept in electrode design. The new electrode configuration is especially useful in applications where increased energy density is desired while minimizing the undesirable characteristics of the high energy density active material.
These and other objects of the present invention will become increasingly more apparent to those skilled in the art by reference to the following description.